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Hi,<br>
Paul Kelly's and Eric Miller's advice worked !! Thanks very much.<br>
As suggested, I replaced /PERMANENT/PROJ_INFO and with the settings from
<a class="moz-txt-link-freetext" href="http://pweb.jps.net/~egm2/grass/STP/">http://pweb.jps.net/~egm2/grass/STP/</a> for stateplane 1983. I also used <br>
<pre>unit: USfoot
units: USfeet
meters: 0.30480060960121920243
</pre>
in the PROJ_UNITS file. This resulted in a correct-looking overlay of census
tract boundaries on a DEM.<br>
<br>
I went with feet rather than meters, based upon the meta-data for the vectors.<br>
<br>
Phil<br>
<br>
Eric G. Miller wrote:<br>
<blockquote type="cite" cite="mid20030302192622.GA29297@calico.local">
<pre wrap="">On Sun, Mar 02, 2003 at 12:13:23PM -0500, Philipp Molzer wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi,
I'm using grass5.0.0 on Linux RedHat8 (intel).
I have a DEM upon which I'd like to overlay some census data (vectors).
The DEM is in UTM format while the vectors are in state plane format.
Both locations are NAD83. Both cover the area of Essex County, New
Jersey, USA. When I use v.proj to bring the vectors from my state plane
location to my UTM location, the resulting vector data has coordinates
that seem to be incompatible with the DEM coordinates. The east and
west bounds of the imported vector layer appear to be way off.
</pre>
</blockquote>
<pre wrap=""><!---->
</pre>
<blockquote type="cite">
<pre wrap="">Source of vectors
Vectors were imported into a location with these specifications:
name: State Plane
datum: nad83
dx: 0.000000
dy: 0.000000
dz: 0.000000
proj: tmerc
a: 0.63782064e+07
es: 0.6768657997291094e-02
x_0: 0.6096012192024384e+06
y_0: 0
k: 0.999975e+00
lon_0: 74d40'w
lat_0: 38d50'n
-----------------------------------------------------------
PROJ_UNITS file:
unit: foot
units: feet
meters: 0.3048000000
</pre>
</blockquote>
<pre wrap=""><!---->
I believe the above projection info is incorrect for New Jersey
State Plane of 1983 (it appears to be the spec for 1927, with the
wrong datum name). The biggest difference, will probably be that
the 1983 coordinates are probably measured in meters. I have the
following projection spec., sans units (since states didn't necessarily
follow the 1983->meters recommendation).
# 2900:State_Plane_1983_New_Jersey
name: State_Plane_1983_New_Jersey
datum: nad83
ellps: grs80
y_0: 0
es: 0.0066943800229
a: 6378137
dx: 0
dy: 0
dz: 0
lat_0: 38.8333333333333
f: 298.257222101
proj: tmerc
lon_0: -74.5
k: 0.9999
x_0: 150000
Replace the mapset/PERMANENT/PROJ_INFO file with the above info, and
replace the PROJ_UNITS file with:
unit: meter
units: meters
meters: 1.0
HTH,
</pre>
</blockquote>
<br>
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